Is cardiac computed tomography a reliable alternative to percutaneous coronary angiography for patients awaiting valve surgery?

Abstract

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether a CT angiogram could replace routine percutaneous coronary angiography for excluding coronary arterial disease for patients undergoing a non coronary cardiac procedure. Using the reported search 595 papers were identified. Eleven papers represented the best evidence on the subject and the author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study comments and weaknesses were tabulated. We conclude that angiography with 64-slice multi-detector CT scanner provides reliable non-invasive imaging to exclude significant coronary artery stenoses prior to valve surgery. The negative predictive value of a normal CT scan is around 97%, thus providing a good alternative to conventional angiography in lower atherosclerotic risk patients. The ability of CT angiography to assess the reduction in luminal diameter is reduced in the presence of calcium deposits, and is also reduced in vessels under 1.5 mm. Further disadvantages include an inability to perform scans in patients with arrhythmias or atrial fibrillation, and a five times increased radiation dose compared to conventional angiography.